Perhaps you should try some spelling variations:
khai duc » khai dich, khai luoc, pham duc
va hanh » van hanh, va thanh, va danh
va khai » van khai, va khao, va kha
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
su sach » so sach, vu sach
ma hoi » mai hoi, xa hoi, ma hoa
vi cau » va cau, ve cau, viet cau
di cau » da cau, diem cau
su sac » su cac, su xac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sac) or (su sach)) ky tang ma hoi. hieu va khai duc va hanh ((vi cau) or (di cau)) theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sac) OR (su sach)) ky tang ma hoi. hieu va khai duc va hanh ((vi cau) OR (di cau)) theo.
• Adding a wildcard symbol may retrieve word variants: ((su sac) or (su sach)) ky tang ma hoi. hieu va khai duc va hanh ((vi cau) or (di cau)) theo*.